高强度钢19MnB4板料冲裁间隙有限元模拟

为了得到高强度钢19MnB4板料冲裁的合理间隙,利用DEFORM构建并模拟了板料厚度1.5 mm,不同冲裁间隙的成形过程。根据模拟结果,分析冲裁力、冲裁功以及断面质量随冲裁间隙的变化趋势。结果表明,厚度为1.5 mm的19MnB4合金板料合理冲裁间隙为0.046 mm.     

冲裁间隙对断面轮廓影响的研究

应用DEFORM-3D软件对304号不锈钢板料在不同冲裁间隙下的冲裁过程进行有限元数值模拟,获得了板料冲裁过程中冲裁力的变化曲线和冲裁件断面。分析了板料冲裁变形过程和不同冲裁间隙下所得到的冲裁件断面轮廓,研究了冲裁间隙对冲裁件断面轮廓的影响。在实际生产中,选用合适的冲裁间隙可以提高冲裁件断面的质量。     

基于Deform的板料冲裁过程有限元模拟与分析

应用Deform商业有限元分析软件,对不同厚度的板料冲裁过程进行模拟计算,获得冲裁过程各阶段应力、应变状态,以及整个过程冲裁力的变化。分析了冲裁工艺参数对板料裂纹生成及板料断裂位置的影响。从而可以根据冲裁过程中材料的应力应变与滑块速度的关系来制定冲裁工艺,编制冲裁力-行程曲线,使得冲裁力变化缓慢,延长贮存在压力机的弹性变形能的释放时间,以大大降低机器的振动与噪声,最终达到静音冲裁的目的。     

基于有限元的板料冲裁模拟研究

使用DEFORM有限元软件进行了不同冲裁间隙的冲裁过程模拟研究,分析了板料冲裁变形过程及断裂分离过程,绘制了冲裁力、断面质量随冲裁间隙变化的趋势图。在此基础上,得到了冲裁间隙-冲裁功曲线变化图形,确定了合理冲裁间隙取值,具有一定的工程应用价值。     

Q235负间隙精密冲裁件断面微观组织变化研究

为了搞清负间隙精密冲裁和普通冲裁材料内部的运动状况,掌握两种冲裁的成形规律,通过负间隙精密冲裁和普通冲裁仿真和实验,针对不同冲裁时的断面进行研究,得到了负间隙精密冲裁和普通冲裁板料内部的成形规律,将负间隙精密冲裁时断面断裂成形裂纹细分为三级,证实了负间隙精密冲裁的挤压成形和普通冲裁的拉伸撕裂成形,并推得了负间隙精密冲裁件断面质量的影响因素及规律。     

合理选择冲裁间隙

本文是在总结我国现有冲裁间隙的研究成果及实际生产经验的基础上,参照了美国工具和制造工程师协会(ASTME)1964年制订的冲裁间隙表而拟订的。一、总则本文介绍的冲裁间隙仅适用于板料的普通冲裁,所提供的三类间隙值,各行业、各单位可根据自己的生产特点合理选用。冲裁间隙系指凸凹模工作部分对应尺寸之差,本文采用双面间隙。     

大冲裁间隙对中厚板冲裁力影响的研究

在30T万能材料拉伸试验机上利用简易快换模具对厚度为5mm、8mm、10mm三种规格的Q235材料进行冲裁试验,通过对试验结果、冲裁变形过程、冲裁时板料的受力情况进行分析,得出了大冲裁间隙对中厚板冲裁时冲裁力的影响规律,并提供了中厚板冲裁时降低冲裁力的方法,为中厚板的冲裁加工提供可靠的理论依据。     

一种新的冲裁间隙实验模具的设计

冲裁间隙是影响冲裁件质量、模具寿命、冲裁力的重要因素,而冲裁间隙实验又是材料加工专业中的基础实验,在专业课程的学习中具有非常重要的作用。在以往的教学中开设冲裁间隙实验时为了改变冲裁间隙的大小,需要多次更换模具,非常不方便。现开发的是一种新的冲裁间隙实验模具,能实现不拆卸模具的情况下快速更换冲裁凸模,从而为实验提供不同的冲裁间隙值,克服了传统实验中多次装卸模具、调试模具的缺点,节约了实验时间,提高了实验的可靠性和安全性。该模具已经申请了实用新型专利,并获授权。     

略论按件选模

在冲压件生产中,获得较好的技术经济效果,必须按照冲压件的技术要求与批量选择相应的模具,即“按件选模”。本文着重探讨一些与常规冲模不同的冲裁模与成形模,供选择时参考。在板料冲压生产中,除了常规的冲裁模与成形模之外,尚有下列模具可以应用于生产。一、按间隙的不同分类 1.合理大间隙冲裁模。其主要优点可以减少制模工时与材料消耗,并能成倍地提高模具寿命。所谓合理大间隙实质上是“按件定隙”,即在满足冲压件质量要求的前提下,选择能使制模成本较低,模具寿命     

模具冲裁间隙标准问题研讨

正1.我国模具冲裁间隙现状冲裁是金属板材加工中非常重要的工艺方法,冲裁间隙是冲裁加工中非常重要的工艺参数。它对于提高模具的使用寿命和保证优良的冲裁断面质量,起到关键性的作用。目前,世界各国采用的间隙是不一样的,我国采用的间隙值很复杂。20世纪70年代前,我国采用的间隙值,是来自于原苏联《冷压手册》,这个标准的双面间隙约为材料厚度的5%~6%,冲裁后断面     

Design of Experiment Based Analysis for Sheet Metal Blanking Processes Optimisation

The blanking of metal parts for electronic components is subjected to a variety of process parameters. In this paper, an experimental investigation into the blanking process was carried out using tools with four different wear states and four different clearances. The aim was to study the effects of the interaction between the clearance, the wear state of the tool and the sheet metal thickness on the evolution of the blanking force and the geometry of the sheared profile. Designed experiments are an efficient and cost-effective way to model and analyse the relationships that describe process variations. The results of the proposed experimental investigation show the strong dependence between the geometrical quality of the blanked part and the magnitude of the force applied on the tool as well as the variations in the process factors .     

Prediction of optimum clearance in sheet metal blanking processes

The blanking process and structure of the blanked surface are influenced by both the tooling (clearance and tool geometry) and properties of the workpiece material (blank thickness, mechanical properties, microstructure, etc.). Therefore, for a given material, the clearance and tool geometry are the most important parameters. The objective of the present work is to develop a methodology to obtain the optimum punch-die clearance for a given sheet material by simulation of the blanking process. A damage model of the Lemaitre type is used in order to describe crack initiation and propagation into the sheet. A comparative study between numerical and experimental results shows good agreement.     

Prediction of the sound pressure level of blanking noise during sheet-metal blanking using servo press with counterforce

In this research, a prediction model of the sound pressure level during blanking using servo press with counterforce was established based on the acoustic theory as well as the vibration equation of punch in the course of breakthrough process. The theoretical values of the sound pressure level of blanking noise were calculated based on the developed prediction model. The variation of the sound pressure level of blanking noise with different parameters was also investigated and compared with the experimental results. It reveals that the blanking noise increases with the shear strength and the thickness of sheet metal, and further the blanking speed. The relative error between the experimental results and the theoretical ones determined based on the prediction model is less than 1.7%, and the application example of the prediction model in batch production is given. The prediction model is thus proved to be promising and efficient for noise prediction during blanking using servo press with counterforce.     

Effect of technological parameters on microstructure and accuracy of B1500HS steel parts in the hot blanking

Hot blanking process could be used for producing diverse fine blanking parts with comprehensive mechanical properties and to solve the problems in the piercing and trimming of press-hardened parts. To explore the optimal hot blanking process and evaluate the effects of some technological parameters on the phase transformation, fracture quality, and dimensional accuracy of the parts, several different blanking temperatures (450–800 °C) and die clearances (8–25%) were used in the hot blanking of B1500HS steel. The experimental results show that as the blanking temperature increases at a certain die clearance, the dimensional accuracy shows a trend of “negative growth–positive growth–negative growth,” and a higher dimensional accuracy of blanked parts can be attained at blanking temperatures 450–500, 600–650, or 750–800 °C. Besides, the burnish zone width increases, and the burnish and rollover zone widths account for ~?80% of the steel sheet thickness at 800 °C. At blanking temperatures 650–800 °C, the microstructure of blanked parts is completely martensite, the microhardness of parts is ~?550 HV, and the perpendicularity of fracture increases as the blanking temperature increases. Parts with a high-dimensional accuracy, better fracture perpendicularity, wide burnish zone, better mechanical properties, and wear resistance can be obtained at blanking temperatures 750–800 °C.     

彩钢板成型机冲裁机构刀具动态仿真与工艺优化

优化彩钢板成型机冲裁机构刀具的冲裁工艺,减小在冲裁薄件时刀具的冲裁力,延长刀具使用寿命,提高冲裁质量.对刀具不同凹刃口的倾斜角度和上下刀具纵向的不同间隙分别进行动态有限元模拟.通过动态有限元仿真结果得出,凹刃口的倾斜角度在4～5°之间较为合适,刀具的纵向合理间隙应为板材厚度的7％左右,有利于实现减小刀具的冲裁力,延长模...     

An experimental analysis of effects of various material tool’s wear on burr during generator sheets blanking

Blanking is one of the most frequently used processes in sheet metal forming. Unlike other forming processes, such as stamping, blanking not only deforms the metal plastically to give the appropriate size and shape, but also ruptures the sheet metal in the desired zones. Among the others, blanking enables manufacturing of electric motor components, such as rotor or stator parts. The parts of the low power commutator motor of rotor and stator are made of generator sheets, which are really difficult to do from the machining point of view. The shock loads and high reaction of the sheet metal of separation surface to the punch surface are presented during the blanking process. In this paper, an investigation has been made to study the effects of punch–die clearance, tool materials, and tool coatings on the wear of blanking tools. In the paper, the feasibility analysis for various materials used for production of the tools for punching the generator sheets is presented.     

叠层金属薄板材料的冲裁特性研究

在冲裁分离过程中,单层与叠层金属板材存在很大的差异。通过对比2者的不同特点,选取并分析微元体的应力应变状态,发现在叠层冲裁过程中,变形区内中间层的材料处在3向压应力状态,表现出很强的可塑性。分析冲裁中各因素对应力状态的影响发现,合理地减小凸模与凹模的间隙可以提高变形区的静水压,抑制裂纹的产生,使冲裁过程控制在塑剪变形阶段。以叠层母线冲孔为例来验证理论分析,试验结果与分析一致,叠层冲裁比同厚度单层冲裁所要求的模具间隙更小,其值取在普通冲裁间隙经验公式的基础上乘以0．4左右的修正系数为宜。     

The Role of Radial Clearance on the Performance of Foil Air Bearings

Load capacity tests were conducted to determine how radial clearance variations affect the load capacity coefficient of foil air bearings. Two Generation III foil air bearings with the same design but possessing different initial radial clearances were tested at room temperature against an as-ground PS304 coated journal operating at 30000 rpm. Increases in radial clearance were accomplished by reducing the journal's outside diameter via an in-place grinding system. From each load capacity test the bearing load capacity coefficient was calculated from the rule-of-thumb (ROT) model developed for foil air bearings.

The test results indicate that, in terms of the load capacity coefficient, radial clearance has a direct impact on the performance of the foil air bearing. Each test bearing exhibited an optimum radial clearance that resulted in a maximum load capacity coefficient. Relative to this optimum value are two separate operating regimes that are governed by different modes of failure. Bearings operating with radial clearances less than the optimum exhibit load capacity coefficients that are a strong function of radial clearance and are prone to a thermal runaway failure mechanism and bearing seizure. Conversely, a bearing operating with a radial clearance twice the optimum suffered only a 20% decline in its maximum load capacity coefficient and did not experience any thermal management problems. However, it is unknown to what degree these changes in radial clearance had on other performance parameters, such as the stiffness and damping properties of the bearings.     

配合间隙对溢流阀稳态液动力的影响

针对稳态液动力影响电液比例溢流阀调压精度的问题,建立了内流式滑阀液动力数学模型,基于CFD仿真平台,构建了考虑配合间隙的滑阀模型,并搭建了试验平台以验证模型的正确性,研究了不同配合间隙对滑阀稳态液动力的影响。结果表明：考虑配合间隙的滑阀模型与试验测试结果有很好的一致性;溢流阀在工作过程中,阀口开度与配合间隙非常接近,随着压力升高,阀口开度变小,射流角接近20°;随着配合间隙增大,阀口开度变小,射流角变大;配合间隙在一定范围内,液动力随着间隙增大而增大,当达到临界值后,配合间隙对液动力的影响变小。     

神经网络在航空活塞发动机排气门故障预测中的应用

针对航空活塞发动机排气门卡阻故障,经过对故障机理的分析,提出了一种利用神经网络对排气门导套与气门杆的配合间障进行预测,以间接预测排气门卡阻故障的方法。将影响排气门积垢速率的因素设定合理的特征值,以这些特征值和发动工作时间作为输入向量,配合间隙作为输出向量,分别建立了GRNN神经网络和BP神经网络预测模型。预测实例表明,GRNN神经网络预测模型具有较高的预测精度、稳定的网络以及较快的收敛速度,预测性能优于BP神经网络模型,预测结果可作为评估排气门卡阻故障发生概率的有效依据。